Communication interface: built-in CH340 USB to serial chip, through the TYPE-C interface to external communications, support for online upgrades antenna,Infrared Remote Control. Supports all key functions, numeric keypad for frequency input. Antenna interface: full band with external antenna, standard BNC external button hole. Speaker output: the use of digital audio amplifier chip, drive 45x45mm large size wide frequency cavity speakers, power 4/5W. Output noise is lower, distortion is small, volume up does not distort, built-in always speaker,circuit design is stereo, stereo channel please set to mono (mixing mode). Headphone output: the use of freight chip, easy to connect to the amplifier, standard 3.5mm audio connector output, speakers and headphones dual-amplifier design, inserted into the headphones, built-in amplifier mute switch to headphone output. Basic operations: ON/OFF button: power switch, encoder (ROTARY) mode switching, long ON/OFF button for 3 seconds to turn on or turn off the power, after the power on, short the encoder once for the volume, continuous short the encoder for the ambient light to choose Function, short once to exit. ROTARY (encoder): Power on is to adjust the frequency, short the on/off button once is for the volume level, and enter the setting interface for the shift function. Short on the center button is step switching, long is to open and EQ. button: bandwidth selection Short in FM mode:Stereo/Mono switching Battery Parameters:3.7V/4000mAh, 18.5Wh, Li-ion Current Consumption:about 3.7V/350mA, using time about 10 hours Power Supply:2 x AAA batteries(Not included batteries) Colour:Silver Material:aluminum alloy Package Contents: 1 set * TEF6686 High-Sensitivity Radio (Differen batches may have different printed words) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.